The third thing to consider when reading a history textbook is how it makes you /feel/.
Because if it makes you feel nothing, that's probably the point.
The pictures of the Vietnam War era in Texas' official textbook for 11th graders are deliberately bland. There are pictures of the 1968 Democratic convention, several soldiers getting out of a UH-60, and one with some napalm smoke in the distance.

The most controversial picture in the chapter is of Mary Ann Vecchio kneeling over the Jeffrey Miller moments after he was killed in the Kent State protests, but there's no caption explaining that students are looking at a corpse.
What you *won't* see is anything that makes you question whether we really are the good guys.
But if you want students to understand how Vietnam could divide the nation, then you're going to have to show them the pictures their grandparents saw in the newspapers and on television at the time.
Let them see Thích Quảng Đức in the middle of his self immolation.

Have them Google search "Vietnam nap-" and let it autocomplete.

Let them debate whether Gen. Nguyễn Ngọc Loan was justified.

And show them the aftermath at My Lai.

But no, that's not what Texas wants for its students. What Texas wants more than anything is for students to feel vaguely positive about their history, even if what it has in its history books isn't representative.
Even if what it has in its history books isn't actually the truth. As I've shown, those things are secondary.
So as you read a history textbook -- or the news, for that matter (since the news is realtime history) -- consider what you're being shown.
Is it really the truth?
Is it truly representative of a wider trend?
And what emotion was this story meant to invoke?
Because what you're looking at has been edited, selected, and published very deliberately.
Sources:
There is a warning tale in depicting decontextualized truth, and it's applicable to social media
https://medium.com/@ryantorres_/burning-monk-a-warning-tale-4574d396a200
Kim Phuc Phan Thi received her 12th and final burn treatment in 2022.
https://www.wionews.com/world/vietnam-wars-napalm-girl-receives-final-skin-treatment-50-years-after-iconic-image-493855
What happened before the execution matters, too.
https://www.thephoblographer.com/2017/02/01/on-this-date-in-1968-eddie-adams-shot-a-pulitzer-winning-photo/
It wasn't something new. It just happened to be photographed.
https://www.historytoday.com/archive/my-lai-massacre